Many electrical systems require input of a plurality of different operator initiated control signals each of which controls a different aspect of the operation of the system. Traditionally a separate manually operated control device, such as a switch for example, has been provided for each such aspect. This can result in an undesirably complicated, bulky and costly grouping of control devices and can cause operator error.
More recently this problem has been addressed by providing multi-function control devices. A single control device of this kind is used to control a plurality of different operations of the controlled apparatus and/or to control a plurality of different electrical circuits. Switches which respond to keystrokes at a computer keyboard or to key operations at certain handheld calculators are examples of multi-function controls of this kind. Remote controls which control both a television set and a video cassette recorder are another.
Circuit control devices typically require visible graphics such as labels and/or calibration markings that identify the function of the control, the settings of the control or which provide other information pertinent to operation of the control device. Permanently imprinted graphics situated adjacent to an operator manipulated component of a control device, such as a switch button or a rotary or slidable knob, can cause problems if the control has different functions during different modes of operation. Labels or other graphics that are appropriate for one function of the control device may not be applicable to another. Only a limited number of different imprinted graphics can be fitted into the immediate vicinity of the operator manipulated component and plural graphics at that location can be confusing to an operator.
Electronic image display screens have been situated in the vicinity of circuit controls to provide graphics that can change instantly when the function or setting of a control is changed. Most prior control systems of this kind can display graphics only at a limited portion of the area around a switch button or turnable or slidable knob as the display screen is situated at one side or above or below the button or knob. The display screen has a sizable marginal region which extends around the image display area of the screen that contains structural framing, seals and electrical conductors. Consequently, the graphics cannot be displayed at locations immediately adjacent to the button or knob as would be desirable to assure that an operator associates the graphics with the particular controls to which they relate and to enable precise setting of controls.
In a limited number of instances, switch buttons have been situated within the actual image display area of an electronic image display screen thereby enabling changeable graphics to be displayed in close proximity to the switch buttons. This has heretofore required complication of the internal construction of the screen itself as the switch buttons extend through holes in the screen or are built into the screen itself. Prior controls of this kind have been limited to use of display screens of the segmented electrode type. A screen of that type can present only a very limited range of different graphics.
Locating of circuit controls at the actual image display area of an electronic image display screen has heretofore been confined to the above described construction in which small switch buttons extend within the screen. The advantages of changeable graphics at any desired location around the perimeter of an operator manipulated control member have not been available with other forms of circuit controls.
With regard to a particular type of circuit control device, remote controls which enable control of electrical apparatus from a spaced apart location were originally limited to controlling of a single type of apparatus such as a television receiver for example. Additional remote controls were needed to control other types of electrical apparatus such as a video cassette recorder. More recent remote controls are adapted to control both a television receiver and a video cassette recorder in two different modes of operation of the single remote control. Multiple purpose remote controls of this kind have heretofore required substantially more switch buttons than a single purpose remote control and are bulkier and more confusing to operate. The prior multiple purpose remote controls are limited to control of a small number of different types of apparatus and useful only for remote control operations.
The present invention is directed to overcoming one or more of the problems discussed above.